Abstract: Halophilic actinomyces can produce abundant secondary metabolites with novel structure and different activity due to their unique physiological characteristics and metabolic mechanism.The study was based on halophilic actinomyces TRM45306 from the extreme environment soil sample collected in Lop nur of Xinjiang.Firstly,the phylogenetic position of TRM45306 was identified by the ways of morphological observation,biological characteristics and 16S rDNA sequence analysis;Secondly,the secondary metabolites were separated from fermentation broth by the joint utilization of various techniques including extraction,silica gel chromatography and gel filtration chromatography;Lastly,the compounds structures were identified by nuclear magnetic resonance methods including ¹³C NMR,1H NMR and comparisons of the spectroscopic data with those reported.The research results show that the TRM45306 was a stain of moderate halophilic Streptomyces,the similarity to the Streptomyces rochei NBRC 12908 (T) was 100%,four compounds were separated from fermentation broth,and their structures were elucidated as 16α-methyl-11β,17α,21-trihydroxyl-9α-pregn-1,4-diene-3,20-dione-21-acetate (Dexamethasone acetate),β-Sitosterol 3-O-β-D-glucopyranoside,Nb-acetyltryptamine and N-(2-(1H-indol-3-yl)ethyl)-propionamide.The research results will be an important theoretical basis for excavation of secondary metabolites of halophilic actinomycetes,and will be of great significance to exploit of actinomycetes resources in extreme environment of Xinjiang.

Key words: halophilic actinomycetes, secondary metabolites, isolation and purification, structure identification